Early growth response gene 1 (EGR1) regulates heparanase gene transcription in tumour cells

Amanda De Mestre, Sudha Rao, June Hornby, Thura Soe-Htwe, Levon Khachigian, Mark Hulett

Research output: Contribution to journalArticle

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Abstract

Heparanase is an endoglycosidase that degrades heparan sulfate chains of heparan sulfate proteoglycans, a key component of extracellular matrix and basement membranes. Studies using heparanase inhibitors and gene silencing have provided evidence to support an important role for heparanase in tumor metastasis and angiogenesis. The expression of heparanase is normally very tightly controlled, however, it is commonly deregulated in tumor cells, which express elevated heparanase activity that correlates with high levels of heparanase mRNA. We recently identified the transcription factor early growth response gene 1, EGR1, as a key regulator of inducible heparanase transcription in T cells. In this study using chromatin immunoprecipitation, we demonstrate for the first time that EGR1 binds to the heparanase gene promoter in vivo. The important question of the role of EGR1 in regulating heparanase transcription in tumor cells was then assessed. Studies were carried out in four epithelial tumor lines of different tissue origin. Functional dissection of the heparanase promoter identified a 280-bp region that was critical for transcription of the heparanase gene. Transactivation studies using an EGR1 expression vector co-transfected with a reporter construct containing the 280-bp region showed EGR1-activated heparanase promoter activity in a dose-dependent manner in prostate or breast adenocarcinoma and colon carcinoma cell lines. In contrast, overexpression of EGR1 resulted in a dose-dependent repression of promoter activity in melanoma cells. Using site-directed mutagenesis the 280-bp region was found to contain two functional EGR1 sites and electrophoretic mobility shift assays showed binding of EGR1 to both of these sites upon activation of tumor cells. Furthermore, the heparanase promoter region containing the EGR1 sites was also inducible in tumor cells and induction corresponded to HPSE expression levels. These studies show that EGR1 regulates heparanase transcription in tumor cells and importantly, can have a repressive or activating role depending on the tumor type
Original languageEnglish
Pages (from-to)35136-35147
Number of pages12
JournalJournal of Biological Chemistry
Volume280
Issue number42
DOIs
Publication statusPublished - 21 Oct 2005
Externally publishedYes

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Transcription
Tumors
Genes
Cells
Growth
Neoplasms
heparanase
Early Growth Response Transcription Factors
Early Growth Response Protein 1
Dissection
Heparan Sulfate Proteoglycans
Electrophoretic mobility
Mutagenesis
T-cells
Chromatin Immunoprecipitation
Gene Silencing
Electrophoretic Mobility Shift Assay
Site-Directed Mutagenesis
Basement Membrane
Genetic Promoter Regions

Cite this

De Mestre, A., Rao, S., Hornby, J., Soe-Htwe, T., Khachigian, L., & Hulett, M. (2005). Early growth response gene 1 (EGR1) regulates heparanase gene transcription in tumour cells. Journal of Biological Chemistry, 280(42), 35136-35147. https://doi.org/10.1074/jbc.M503414200
De Mestre, Amanda ; Rao, Sudha ; Hornby, June ; Soe-Htwe, Thura ; Khachigian, Levon ; Hulett, Mark. / Early growth response gene 1 (EGR1) regulates heparanase gene transcription in tumour cells. In: Journal of Biological Chemistry. 2005 ; Vol. 280, No. 42. pp. 35136-35147.
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De Mestre, A, Rao, S, Hornby, J, Soe-Htwe, T, Khachigian, L & Hulett, M 2005, 'Early growth response gene 1 (EGR1) regulates heparanase gene transcription in tumour cells', Journal of Biological Chemistry, vol. 280, no. 42, pp. 35136-35147. https://doi.org/10.1074/jbc.M503414200

Early growth response gene 1 (EGR1) regulates heparanase gene transcription in tumour cells. / De Mestre, Amanda; Rao, Sudha; Hornby, June; Soe-Htwe, Thura; Khachigian, Levon; Hulett, Mark.

In: Journal of Biological Chemistry, Vol. 280, No. 42, 21.10.2005, p. 35136-35147.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Early growth response gene 1 (EGR1) regulates heparanase gene transcription in tumour cells

AU - De Mestre, Amanda

AU - Rao, Sudha

AU - Hornby, June

AU - Soe-Htwe, Thura

AU - Khachigian, Levon

AU - Hulett, Mark

PY - 2005/10/21

Y1 - 2005/10/21

N2 - Heparanase is an endoglycosidase that degrades heparan sulfate chains of heparan sulfate proteoglycans, a key component of extracellular matrix and basement membranes. Studies using heparanase inhibitors and gene silencing have provided evidence to support an important role for heparanase in tumor metastasis and angiogenesis. The expression of heparanase is normally very tightly controlled, however, it is commonly deregulated in tumor cells, which express elevated heparanase activity that correlates with high levels of heparanase mRNA. We recently identified the transcription factor early growth response gene 1, EGR1, as a key regulator of inducible heparanase transcription in T cells. In this study using chromatin immunoprecipitation, we demonstrate for the first time that EGR1 binds to the heparanase gene promoter in vivo. The important question of the role of EGR1 in regulating heparanase transcription in tumor cells was then assessed. Studies were carried out in four epithelial tumor lines of different tissue origin. Functional dissection of the heparanase promoter identified a 280-bp region that was critical for transcription of the heparanase gene. Transactivation studies using an EGR1 expression vector co-transfected with a reporter construct containing the 280-bp region showed EGR1-activated heparanase promoter activity in a dose-dependent manner in prostate or breast adenocarcinoma and colon carcinoma cell lines. In contrast, overexpression of EGR1 resulted in a dose-dependent repression of promoter activity in melanoma cells. Using site-directed mutagenesis the 280-bp region was found to contain two functional EGR1 sites and electrophoretic mobility shift assays showed binding of EGR1 to both of these sites upon activation of tumor cells. Furthermore, the heparanase promoter region containing the EGR1 sites was also inducible in tumor cells and induction corresponded to HPSE expression levels. These studies show that EGR1 regulates heparanase transcription in tumor cells and importantly, can have a repressive or activating role depending on the tumor type

AB - Heparanase is an endoglycosidase that degrades heparan sulfate chains of heparan sulfate proteoglycans, a key component of extracellular matrix and basement membranes. Studies using heparanase inhibitors and gene silencing have provided evidence to support an important role for heparanase in tumor metastasis and angiogenesis. The expression of heparanase is normally very tightly controlled, however, it is commonly deregulated in tumor cells, which express elevated heparanase activity that correlates with high levels of heparanase mRNA. We recently identified the transcription factor early growth response gene 1, EGR1, as a key regulator of inducible heparanase transcription in T cells. In this study using chromatin immunoprecipitation, we demonstrate for the first time that EGR1 binds to the heparanase gene promoter in vivo. The important question of the role of EGR1 in regulating heparanase transcription in tumor cells was then assessed. Studies were carried out in four epithelial tumor lines of different tissue origin. Functional dissection of the heparanase promoter identified a 280-bp region that was critical for transcription of the heparanase gene. Transactivation studies using an EGR1 expression vector co-transfected with a reporter construct containing the 280-bp region showed EGR1-activated heparanase promoter activity in a dose-dependent manner in prostate or breast adenocarcinoma and colon carcinoma cell lines. In contrast, overexpression of EGR1 resulted in a dose-dependent repression of promoter activity in melanoma cells. Using site-directed mutagenesis the 280-bp region was found to contain two functional EGR1 sites and electrophoretic mobility shift assays showed binding of EGR1 to both of these sites upon activation of tumor cells. Furthermore, the heparanase promoter region containing the EGR1 sites was also inducible in tumor cells and induction corresponded to HPSE expression levels. These studies show that EGR1 regulates heparanase transcription in tumor cells and importantly, can have a repressive or activating role depending on the tumor type

U2 - 10.1074/jbc.M503414200

DO - 10.1074/jbc.M503414200

M3 - Article

VL - 280

SP - 35136

EP - 35147

JO - The Journal of Biological Chemistry

JF - The Journal of Biological Chemistry

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